Where is this Item Modification?

I distinctly remember reading about an item modification guideline that was effectively the opposite of the core guideline that restricted who could use the item to a specific group. This opposite guideline was basically "everybody EXCEPT the identities you work in can use the item." I can't for the life of me remember which book it was. I ask because my magus is currently upgrading the traps in his sanctum, and such an item option would be helpful to the point where I'd like to nudge my SG into arranging a story for me to find it. Can anybody give me a book and page number?

No, and I surely do wish I could.
It could be argued to be extrapolated from the "works only for people on this list" though.
I'd suggest talking it over with your troupe.

Oh look, an up to 15 breakthrough points research project :smiley:

Is this a thing from the books, or a suggestion? Either way I'll ply it to my SG, but it would be very nice if I could actually find the bit in the book... Hm. Best keep looking, then. To HoH:TL! runs off

If the group you wish to prevent using it has some kind of commonality to them I think you could use everyone except this group...

An interesting point is that the example for Effect Use is "to you and your current apprentices" (emphasis is mine) and later, it even mentions a somewhat restricted, yet unlimited group of "anyone in my direct magical lineage." So, a magus might create an item with such a restriction, yet not have anyone in his magical lineage, or create an item that he and his apprentices use, but once they pass their gauntlet they are no longer apprentices and can no longer use the item. The idea of limiting Effect Use is to allow "us" to use it while preventing "them" from being able to use it. Everyone except blank is a legitimate list of people, IMO.

Suggestion. I'm stealing it as one anyway :stuck_out_tongue:

I'm playing a research for the house focused verditius (As in he's trying to make things that only verditi can do to improve their standing in the order), and has a lot of low end breakthroughs to work on for the next few years.